Imagine the Surfer using his Cosmic Powers to the fullest measure ever with the intent to finish his opponents for good. For instance, a truly omnipotent being offering him the return of his home world, but that he must kill, or get rid for good the following opponents like HP Doomsday, Majestic, and Superboy Prime. Now, the Surfer will utilize all of his powers to its Maximum capacity. Thus, here's my take:

1) H/P Doomsday

The Surfer would fly at faster than light speed, and phased through him leaving a Black Hole inside Doomsday's chest; or another scenario would be manipulating Doomsday genetic make-up and thus interfering with his reactive adaptation, and then atomizing him (or reducing him to atoms).

Since the Surfer can reduce things to atoms if he chooses to; or increase the proportions of anything (See the Silver Surfer/Superman crossover- when the Surfer increased the miniature size of Metropolis along with its Mega structures, and living organism- like people, plants and insects to its regular size)- he can reduce Superboy Prime to a small midget like cretin about 5 inches tall. He will then take him as a mascot to his Heralds friends to escape the boredom destiny of serving a Tyrant in Galactus- and taking his crap all the time. He will do labor around Galactus ships at super-speed (or finding Planets for Galactus to consume; while they enjoy a much needed vacation time visiting other Planets), and when he gets out of hand- like doing some obscene gestures (like showing the middle finger at them close to the speed of light) he will be blasted or swat from side to side; since the Heralds have Cosmic awareness and can see things much father away than the speed of light. However, don't worry so much about Superboy Prime- he can take them regular cosmic blasts. However, he shouldn't get on the Heralds nerves or else...

Well, that's my take, what would be your take on this one?

By the way, here are some samples of the Silver Surfer's Cosmic feats for your enjoyment: